● Creating Rich Media with QuickTime, Part III - 荔园在线 | 深圳大学学生论坛,荔园晨风BBS,深大在线网站

荔园之美，在春之萌芽，在夏之绽放，在秋之收获，在冬之沉淀

发信人: Name (冷雨无晴), 信区: Multimedia
标题: Creating Rich Media with QuickTime, Part III
发信站: 荔园晨风BBS站 (Tue May 29 22:12:14 2001), 转信

Creating Rich Media with QuickTime, Part III

By Barb Roeder

整理/搜新网吴朝相

More Interactivity with Sprites

Sprites are an incredibly efficient way to add animation and
interactivity to your QT movies. Sprites are vector-based animations,
meaning that instead of sending new images for every frame of motion,
only one image and then its position and other properties are sent as
time progresses in the movie. The viewer's computer performs the task of
creating a moving object based on this information.

There are many different sprite properties that can be combined to
create different effects. You can specify a transformation matrix -- a
set of nine numbers describing the sprites position, scale and rotation.
You can set its depth, allowing multiple sprites in a track to move
in front of or behind each other. The source for the sprite image can be
a bitmap, a video track, or any other media that QT can display. For
some very cool examples of sprite tracks, check out the links listed
at the end of this article.

A basic use for a sprite track is to create buttons within your movie.
Thus, when HREF tracks are requesting URLs from various places and under
various connection speeds, you can pause the movie automatically
using a sprite. Users can continue by pressing play when they are
ready to move on.

Creating Sprites requires specialized authoring tools, some of which are
listed at the end of this article. If you are interested in pursuing
this type of animation/interactivity for your web movies, your best
bet is to invest in one of these tools and learn more from some of the
other references listed as well.

Removing Buffering Problems with Flash

Another important feature of QT is the Flash track. Again, Flash is an
excellent way to add new media elements to your movie without
significantly increasing its bit rate. A brief description of some
examples and a look at those listed in the reference sections may just
inspire you to go beyond simple video and audio for your Web site.

A Flash animation placed at the beginning of a movie can help ease
"buffering" requirements and give the user more immediate
gratification when clicking on a movie link. It's also a useful way to
add a short commercial to your movie.

Flash sprites can also be used in QT movies -- they have somewhat less
features then QT sprites. An excellent description of the differences
can be found in the Apple Developer Series book, QT for the Web.

Images for Backgrounds and Slide Presentations

As part of a larger media package, single frame images can be a useful
component for keeping data rate requirements down as well. In addition,
many corporate communications and distance learning applications can be
accomplished with slide shows and voice-overs. QT adds some nice
features to such a presentation allowing you to use images in a whole
host of ways within your streaming content. If some of your audience can
be reached with broadband connections, you can set up QT alternates
with transition effects between the slides and video of the speaker to
accompany the presentation as well.

A basic slide presentation is created using the Open Image Sequence
command in the File menu. You will need to create your slides as
individual files, numbering them consecutively: Slide1, Slide2, Slide3.
You can export a PowerPoint presentation in this manner as well. To add
an audio track and effects, follow these steps:

1. Open the Image Sequence in QT, which will create a movie with each
slide occupying one second.

2. Open a midi sound track or prerecorded voice-over for the
presentation you want to synchronize.

3. Select each slide and copy it. Then select the audio segment you want
to play during that slide and choose Add-Scaled in the Edit Menu. The
slide becomes one frame, with its duration equal to the audio segment
selected. Repeat for all your slides.

4. Again, make sure you save your movie without dependencies.

If you want to experiment with effects, you can get a free application
from Apple's web site called MakeEffectsMovie

Or, if you anticipate creating slide presentations on a regular basis,
you should consider a more sophisticated editing tool, some of which are
listed at the end of this article.

It’s a Wrap

By defining media elements such as text, animations and sprites into a
delivery architecture, QT movies can reach beyond the boundaries of
traditional video and television applications. With all the features
touched upon in this article, it's no wonder QT was chosen as the format
for the MPEG-4 standard for media production and distribution.
Developing streaming media using QT can add new features and
interactivity to your content in unique ways, separating your business
from the crowded confines of this marketplace.

--
※ 来源:·荔园晨风BBS站 bbs.szu.edu.cn·[FROM: 192.168.28.220]

荔园在线首页友情链接：深圳大学深大招生荔园晨风BBS S-Term软件网络书店